Glass



UNITED STATES PATENT OFFICE.

MAURICE A. SMITII, OF JEANNETTE, II?ENNSYLVAN'IA, ASSIGNOR T0 McKEE GLASS COMPANY, OF JEANNETTE, PENNSFLVANIA, A CORPORATION OF PENNSYLVANIA,

GLASS.

No Drawing.

My invention relates to the manufacture of g a es, and more particularly to'glass havin a low co-efficient of expansion which wi l withstand an extreme variation of temperature both as to heat and cold. Difl'erent formulas for glasses of low co-efiicient of expansion have been employed, but many of these while standing up under extreme heat conditions will not stand up under extreme conditions of temperature below freezing.

In my improved glass I employ broadly speaking sand, boric oxid, alumina, sodium nitrate and arsenic. The proportions of these ingredients in a batch giving good re sults are as follows:

Sand (SiO 60% Boric oxid (B 0 10% Alumina (A1 05) 7 Sodium nitrate (NaNO,).... 9% White arsenic (AS203) 1% Calcium carbonate (CaCO,). 3%

Sodium carbonate (Na CO,) 10% Specification of Letters Patent.

These percentages, however, may differ somewhat, and I do not wish to confine myself to the exact proportions stated. Not only 15 the glass made from the above formula suitable for extreme degrees of low temperature, but it will also withstand extreme conditlons of temperature below freezing.

What I claim is 1. A glass having low coefficient of expanslon and high resistance to high and low temperatures, said glass being made from a batch consisting of a preponderance of silica, smaller amounts of boric oxid, alumlna, sodium nitrate and sodium carbonate, and still smaller amounts of calcium carbonate and arsenic trioxid.

2. A glass made from a batch composed of the following ingredients in approximately the proportions stated: 60% of silica, 10% of boric oxid, 7% of alumina, 9% sodium nitrate, 1% of arsenic trioxid, 3% of calcium carbonate and 10% of sodium carbonater In testimony whereof, I, the said MAURIon A. SMITH, have hereunto set my hand.

MAURICE A. SMITH.

Witnesses:

'ROBT. I). To'r'rnN, .JOHN F. WILL.

Patented Jan. 18, 1921. Application filed July 15, 1918. Serial No. 244,886. 

